1. Field of the Invention
The invention relates to an ink ribbon cassette that lodges ink ribbon and a printing apparatus that includes such an ink ribbon cassette.
2. Related Background Art
FIG. 16 is a diagram showing a structure of a conventional ink ribbon cassette.
As shown by FIG. 16, in an ink ribbon cassette 1, an ink ribbon 3 is sandwiched and is taken into an ink ribbon lodging section 6 by rotation of a drive gear 10 and a transfer gear 7. The ink ribbon 3, while guided by an embankment 4a formed on lower cover 12 and an embankment 4b that will be mentioned below, is drawn out from the ink ribbon lodging section 6 as a strip of ink ribbon.
FIG. 17 is a longitudinal section diagram showing a conventional embankment part.
As shown in FIG. 17, the embankment 4a is formed on the lower cover 12 and the embankment 4b is formed on an upper cover 11. Then, because the ink ribbon 3 is drawn out while being controlled from two sides (i.e. along a vertical direction in FIG. 17) through the embankment 4a and the embankment 4b, the ink ribbon 3 dose not overlap and does not “dash out.” (e.g. refer to patent document 1).    Patent document 1: Japan utility model publication H05-035327.
However, in order to prolong the life of the ink ribbon cassette 1, it is necessary to extend the length of the ink ribbon 3.
FIG. 18 is a diagram showing an operation of a conventional ink ribbon cassette. As shown in FIG. 18, to extend the length of the ink ribbon 3, the ink ribbon 3 is difficult to arrange to be properly lodged. As illustrated, the ink ribbon 3 falls into a state of disorder as shown at area H. Further, the back part of the ink ribbon 3 outstrips the front part of the ink ribbon 3 as shown at area F2.
In such a state, there is the following problem. That is, in the conventional ink ribbon cassette 1, though the ink ribbon 3 does not dash out by the embankment 4a and the embankment 4b, front and the back parts of the ink ribbon 3 are synchronously drawn out because of a friction caused when the ink ribbon 3 is drawn out. Then the ink ribbon 3 moves across the embankment 4a and the embankment 4b as shown at area G2, and therefore the ink ribbon 3 has a dual movement causing a ribbon jam.